To be candid, I don't know. It certainly looks that way and that Charles is not born a Morgan. There is not yet a record with Frances Wall attached to fhe Morgan name.
Rodney53
None of us are certain of the above. Please bear in mind the name I am citing is HALL, not WALL (as you say, you have only seen it in hand written notes- the confusion would be easy)
Speculating -with a little logic applied-there was not a marriage between John MORGAN and Frances because she was still married to James DEAN.
His war service history is indexed at NAA and shows he was apparently on active service at the time of the conception of Charles John, thus, father not named on the birth record.
He was a market gardener of Narre Warren and Francis (sic) was his NOK.
The pair appear together on the Electoral Roll and I will type the details in a moment.
He died in 1954, after the death of John MORGAN, so there was not opportunity for a late marriage through widowhood for Frances.
Obituary James DEAN of NARRE WARREN 1954. To Springvale.
No wife mentioned but some children are correct for the recorded births.
http://trove.nla.gov.au/newspaper/article/218508357 James -Official Discharged from the services in July / August 1919
Joined up May 1916
A welcome home in May 1919
http://trove.nla.gov.au/newspaper/article/218508357 Sue